I would try starting small and see what type of gun your trying to create inside (Blender since you seem like a beginner it’s all about practice and learning.
For creating gun models this can be done in a software rather then creating them inside studio however it could be made with normal parts if necessary, start small and slow learn the software first before attempting to create variety of weapons basically learn the curve and ropes around blender, see which software your more comfortable in using.
Watch a few beginner tutorials to get the hand and curve around blender and learn the tools, you may want to watch series to get an overall understanding of the (interface, tools, workflow and more). There are many resources on channels that go into details about blender it would be good to take notes, to take along the process.
I’ll consider viewing a few decent tutorials like (donut & mug) just to get comfortable with the version and tools. I’ll consider doing your own little research since questions like this can be easily answered;