Hi @danielcard51553
Before opening the laptop read ''Disabling the built-in battery'' on p.66 (p.72 of 112 pdf) of the [https://download.lenovo.com/pccbbs/mobiles_pdf/t560_p50s_hmm_en_sp40k04930_01.pdf|hardware maintenance manual] for the laptop.
Then go to p.68 and p.77 (74 & 83 of 112 pdf) respectively, to see how to remove the battery, base cover and memory modules
According to the [https://psref.lenovo.com/syspool/Sys/PDF/ThinkPad/ThinkPad_P50s/ThinkPad_P50s_Spec.PDF|specifications] for the laptop, it supports 32GB max / PC3-12800 1600MHz DDR3L, non-parity dual-channel capable memory modules in two DDR3L SO-DIMM sockets i.e. 2 x 16GB modules.