Method for processing a planar substrate, preferably suitable for medical purposes, comprising a porous layer, in particular which in turn comprises a foam layer or a textile, in particular a fiber stack and/or a fiber fabric, wherein the method comprises the steps of: step i) providing the substrate, wherein the substrate has a first outer side and a second outer side, step ii) placing the substrate onto a work surface, wherein the first outer side contacts the work surface in a planar manner after the placement, step iii) applying a template which has a contact side and an upper side, wherein the template preferably has at least one opening, wherein the contact side of the template is applied during application to the second outer side of the substrate facing away from the working surface, wherein the template covers a covered partial region of the substrate and a free partial region of the substrate is uncovered by the template, step iv) pressing the template in the direction of the work surface by means of a magnetic force acting directly on the template, wherein the template comprises ferromagnetic material for this purpose, wherein the substrate is held in its position on the work surface by pressing the template and preferably compressed in its extension from the first outer side to the second outer side, wherein a permanent magnet and/or an electromagnet is/are arranged in or below the work surface so that the magnetic force oriented toward the work surface can be exerted on the template by means of the permanent magnet and/or the electromagnet, step v) processing at least a part of the free partial region of the substrate, wherein processing preferably comprises separating a part of the free partial region of the substrate which projects beyond the upper face of the template, and/or wherein processing comprises applying a substance to the free partial region of the substrate, preferably step vi) cutting the edges of the substrate and/or dividing the substrate in order to obtain a plurality of pieces, wherein cutting and/or dividing takes place in particular by a cut guided substantially vertically to the extension plane of the substrate, preferably step vii) applying a planar material layer to the first outer side and/or the second outer side of the substrate or one of the pieces, preferably step viii) sterilising and/or packaging the substrate or a piece of the substrate, wherein two of, preferably a plurality of, preferably all of, steps i) to viii) preferably occur in the sequence just mentioned. step i) providing the substrate, wherein the substrate has a first outer side and a second outer side, step ii) placing the substrate onto a work surface, wherein the first outer side contacts the work surface in a planar manner after the placement, step iii) applying a template which has a contact side and an upper side, wherein the template preferably has at least one opening, wherein the contact side of the template is applied during application to the second outer side of the substrate facing away from the working surface, wherein the template covers a covered partial region of the substrate and a free partial region of the substrate is uncovered by the template, step iv) pressing the template in the direction of the work surface by means of a magnetic force acting directly on the template, wherein the template comprises ferromagnetic material for this purpose, wherein the substrate is held in its position on the work surface by pressing the template and preferably compressed in its extension from the first outer side to the second outer side, wherein a permanent magnet and/or an electromagnet is/are arranged in or below the work surface so that the magnetic force oriented toward the work surface can be exerted on the template by means of the permanent magnet and/or the electromagnet, step v) processing at least a part of the free partial region of the substrate, wherein processing preferably comprises separating a part of the free partial region of the substrate which projects beyond the upper face of the template, and/or wherein processing comprises applying a substance to the free partial region of the substrate, preferably step vi) cutting the edges of the substrate and/or dividing the substrate in order to obtain a plurality of pieces, wherein cutting and/or dividing takes place in particular by a cut guided substantially vertically to the extension plane of the substrate, preferably step vii) applying a planar material layer to the first outer side and/or the second outer side of the substrate or one of the pieces, preferably step viii) sterilising and/or packaging the substrate or a piece of the substrate, wherein two of, preferably a plurality of, preferably all of, steps i) to viii) preferably occur in the sequence just mentioned.