It's very cold for the last several weeks, and after about a month on
not
driving my 307SW I am not able to start the engine, batter has no
capacity
due to no driving recently, and low temp makes battery even more weak.

What is a procedure to follow in that case? I know that on some
old-fashioned
standard car I would take out battery, fill it up, put it back and
that's it.
Or I would use cables to "borrow" some current from the battery of my
2nd car while it is running, would start the engine of my empty batter
car,
and that's it.
But with car like 307 loaded with electronic, what I have to do to avoid

any damage of electronic or reset of my 307?

Thanks a lot!