Yes I have asked for help before. I guess my dream would be Head of IT one day. Cancer took 10 years and addiction took 5 years. Now I am 40 and want to improve myself.
I feel maybe I didnt say it right. It's a sign of a good Sys Admin to ask, especially when in doubt so feel free to ask anytime and about anything. After all, as they say, there are no stupid questions, only stupid answers. My comment was more about the lack of information and details. Think for example if I was to say to you, "I have a problem with my PC, help". What did I actually say? nothing. My question will only make you ask me more questions like what kind of PC, what kind of problem, and so on. It's a skill you must develop in order to first help yourself and second help your place of work. Ask in details and assume the other doesn't have a clue. Just because we know something or experience a situation, doesn't mean everyone else does. Regardless, don't ever feel bad for asking (if you did) and I'm sure with your attitude and thirst for knowledge, one day you will become the head of IT (tho careful what you ask for, cause it might come true
)
Now to your question. I can't give a definite answer as the firm you guys hired, only knows. There are several ways to do a migration, from custom-made scripts via Powershell, to programs that deal with such issues like SPMT or Kernel Migrator (google as always), etc. As I said above tho, no harm in asking. You can tell them that you seek to improve your admin skills and you are wondering if they can share info on how they will do it. I'm positive they will explain or give you pointers.
As for your personal knowledge, hypervisors will come to your rescue. You can get a test server or workstation (I'm sure you will have a spare one somewhere) set 2 VMs, one with a virtualized SharePoint server, and one VM with a file server similar to what you guys use, upload some files (programs from here are a good option) to the file server and experiment by reading the manual or guides of SPMT by MS/Others. Pay attention to details, notice the limitations (for example no file larger than 15 GB) and play without risk.
Here is a small link to get you started
https://sharepointmaven.com/how-to-migrate-file-shares-to-sharepoint-online-using-microsoft-sharepoint-migration-tool/
Hope it helped you, fellow Admin, and since this thread now exceeds the purpose of the help and request section, I will close the thread but feel free to contact me anytime.