Erik Kostson
Ansys Employee
Hi there seems to be something with the UI in vers. 2021 R2, and this might be defect (thanks for brining it to our attention - it will hopefully be fixed in the next upcoming releases).

Use input files and commands straight away (most of the apdl use is not via the ui, only command inputs - actually there are some things we can not do with the UI, and can only be used via command inputs).

So for a nodal force use:
F,1,FX,100
(explain: !!!! F, NODE NR, Lab, VALUE, VALUE2, NEND, NINC)

Also see the F command for more info on how to use it.

There are many tutorial in the help manual showing the input files for simple models that you can go through.

E.g., verification manual example 3 (VM3).

So use the command inputs and solve them directly and do not use the UI so much if possible.

All the best

Erik