Method for assembling a foldable supporting structure for covering a cylindrical structure, in particular a tank, comprising: - Providing a foldable supporting structure for a cover of a cylindrical structure, in particular a tank, comprising ∘ a central element with a center axis ∘ at least three beams attached to the central element each with at least two arms that are movable relative to one another, ∘ wherein a maximum extension (E MP1) of the beams in radial direction from the center axis in a first assembly position is smaller than a maximum extension (E TP) of the beams in radial direction from the center axis in a supporting position, wherein ∘ the foldable supporting structure is designed in such a way that in all further assembly positions (MP2, MP4, MP5, MP6, MP7, MP8) between the first assembly position and the supporting position a maximum extension (Ev) of the foldable supporting structure in vertical direction corresponds to a maximum of 80% of the maximum extension (E TPR) of the beams in radial direction from the center axis in the supporting position, - preferably providing a buckling stiffener ring and/or a support bracket, in particular at an upper end of the cylindrical structure, - Lifting of the supporting structure in the first assembly position over the cylindrical structure, - Moving the supporting structure into the supporting position, - Fastening of the supporting structure to the upper end of the cylindrical structure, preferably to the buckling stiffener ring and/or to the support bracket, wherein - in all further assembly positions (MP2, MP4, MP5, MP6, MP7, MP8) between the first assembly position and the supporting position, a maximum extension (Ev) of the foldable supporting structure in vertical direction corresponds to a maximum of 80% of the maximum extension (E TPR) of the beams in radial direction from the center axis in the supporting position, and/or - one, several or all steps are performed in such a way that in all further assembly positions (MP2, MP4, MP5, MP6, MP7, MP8) between the first assembly position and the supporting position a maximum extension of the foldable supporting structure in vertical direction corresponds to a maximum of 80% of the maximum extension of the beams in radial direction from the center axis in the supporting position. - Providing a foldable supporting structure for a cover of a cylindrical structure, in particular a tank, comprising ∘ a central element with a center axis ∘ at least three beams attached to the central element each with at least two arms that are movable relative to one another, ∘ wherein a maximum extension (E MP1) of the beams in radial direction from the center axis in a first assembly position is smaller than a maximum extension (E TP) of the beams in radial direction from the center axis in a supporting position, wherein ∘ the foldable supporting structure is designed in such a way that in all further assembly positions (MP2, MP4, MP5, MP6, MP7, MP8) between the first assembly position and the supporting position a maximum extension (Ev) of the foldable supporting structure in vertical direction corresponds to a maximum of 80% of the maximum extension (E TPR) of the beams in radial direction from the center axis in the supporting position, ∘ a central element with a center axis ∘ at least three beams attached to the central element each with at least two arms that are movable relative to one another, ∘ wherein a maximum extension (E MP1) of the beams in radial direction from the center axis in a first assembly position is smaller than a maximum extension (E TP) of the beams in radial direction from the center axis in a supporting position, wherein ∘ the foldable supporting structure is designed in such a way that in all further assembly positions (MP2, MP4, MP5, MP6, MP7, MP8) between the first assembly position and the supporting position a maximum extension (Ev) of the foldable supporting structure in vertical direction corresponds to a maximum of 80% of the maximum extension (E TPR) of the beams in radial direction from the center axis in the supporting position, - preferably providing a buckling stiffener ring and/or a support bracket, in particular at an upper end of the cylindrical structure, - Lifting of the supporting structure in the first assembly position over the cylindrical structure, - Moving the supporting structure into the supporting position, - Fastening of the supporting structure to the upper end of the cylindrical structure, preferably to the buckling stiffener ring and/or to the support bracket, wherein - in all further assembly positions (MP2, MP4, MP5, MP6, MP7, MP8) between the first assembly position and the supporting position, a maximum extension (Ev) of the foldable supporting structure in vertical direction corresponds to a maximum of 80% of the maximum extension (E TPR) of the beams in radial direction from the center axis in the supporting position, and/or - one, several or all steps are performed in such a way that in all further assembly positions (MP2, MP4, MP5, MP6, MP7, MP8) between the first assembly position and the supporting position a maximum extension of the foldable supporting structure in vertical direction corresponds to a maximum of 80% of the maximum extension of the beams in radial direction from the center axis in the supporting position.