Complex sentence: To 4th Panzer Army's right (eastern) flank was 17th Army, and from here the front ran southeast to Olomouc, where the 1st Panzer Army was deployed.
Split into simpler sentences: To 4th Panzer Army's right (eastern) flank was 17th Army. From here the front ran southeast to Olomouc, where the 1st Panzer Army was deployed.