You have a very nice motor there, I like the valve gear and would like to see it in the final loco.
These are my ideas, so read them in that perspective.
I would draw for myself a figure (Pin Man) to use as a yard stick.
You have a couple of types of loco you can make
A pressure steamer. which runs on a filled steam boiler.
Take your time. I often have to have several goes at certain bits on a train
Use card as a material I used it as modelling material for years. I made boats out it when I started after WW11 when there was little else. My glue was starch glue made from flour paste.
There are lots of material on the web and on this site.
Make up mock ideas from paper.
Use the experts on this site i do, all the time. I often see what I want to see others see it as it is.
Keep asking questions.
Keep posting pics as you progress
Can you get PVA glue where you are
Good luck. Ralph