Is the company US based?
I was in military acquisition for many years, including Foreign Military Sales, specifically in manned and unmanned aircraft. For instance, I worked with Spain on their purchase of H-60 helicopters.
I am sure you know the below, but it bears repeating for US based acquisition.
There are numerous US regulations covering who, what, when and how concerning the area you may go into.
ITAR is the specific group of legislation and laws governing US traffic in arms.
Wiki has a good overview:
https://en.wikipedia.org/wiki/International_Traffic_in_Arms_Regulations
There are also laws governing YOUR qualifications and required steps to become registered and certified.
That is just the US...every country has similar rules and regulations.
In the US, all procurement(s) of a certain dollar value must go through FEDBIZOPS, even commodities like ammunition.
What is FedBizOpps
Also, your company (doesn't matter the country of origin) must have a contract vehicle in order to sell to the government - in commodities likely a GSA schedule that you have been certified to use.
I would also get familiar with, again for the US, the applicable FAR clauses. Again, Wiki has a good overview:
https://en.wikipedia.org/wiki/Federal_Acquisition_Regulation
I could go on and on. The above is just for commodities. If your company has a new or unique application you are trying to sell, the research and development trail is even more complicated!
PM for my contact info if you'd like. My knowledge base is mostly US but I have done business in other countries.