The verb "to found," meaning "to establish" or "set up" has these principal parts:
found – founded – founded
The verbs in your sentence are correct. The if clause contains the past form in a present unreal conditional:
If I were you...
The main clause contains would + the simple form of the verb:
I would (I'd) found a company.
It's easy to confuse the verb "find" with the verb "found. The principal parts of "find" are find – found – found.
Here are some examples:
Whenever I shop in that store, I find what I want.
After looking for my lost document for two hours, I finally found it.
The lost puppy was found sleeping in the back of the car.
If I were you, I would find the director right away and explain the situation
They're going to found a new college on that site.
A religious group founded that college in 1798.
The agricultural college was founded in 1865.
If I were you, I would found a company.