I do played drums for years and I am trying to give it a go with finger druming, so we are on the same learning boat right now.
What I have done first and foremost, is to buy a Drum Pad.
To be more clear I bought an AKAI Professional MPD218 midi controller, but any similar USB midi controller will work.
The pads on keyboards are not that great, so go for a dedicated controller. They are kind of cheap.
After that I just set up a drum rack in Ableton and sorted the keys to match what I think is an easier setup than the default one.
In one column, I put the kick below, snare just above it, and hi-hat above the snare.
This way with one hand and three fingers you can do a basic rythm.
Then set up the metronome and listening to it through your headphones try to match the kick in the first and third beat, the snare in the second and fouth and the hi hat first in second and fourth and then in every beat.
From there ... just keep going.
Remember to start in a slow tempo and progresively go up.
What matters is the rythm, the speed comes with time.