Here the University has closed off access to instruments, but keyboard students are still being expected to meed certain requirements. Two of us were given Axiom Pro 61 Midi controller keyboards to get us through. They don't appear to make sound on their own or have their own speakers. They attach to a computer via USB. It would be a great help to both of us if someone could please provide clear instructions on how to make LMMS simply make these keyboards sound like a piano through our laptop speakers. I use a Windows 10 x64 PC, and my friend uses a Macbook with the latest software. You have no idea how much this would help us. We're desparate. Thank you in advance!
Assuming you haven't read it already, does this guide help? https://lmms.io/wiki/index.php?title=Using_MIDI
There's a section on how to get started and it begins right at the very start with the order you have plug things in / switch them on / start them up and takes you through to linking the keyboard to one of the LMMS instruments.
I haven't tried this myself, but it looks like it's got everything covered.