Il faut is a very common French expression meaning:
It uses il, but this il does not refer to a specific person. It is an impersonal expression.
So:
French uses il faut very often where English might simply use must, need to, or have to.
Both are possible, but they feel slightly different.
Because this sentence comes from a manual, il faut sounds natural and neutral. It presents the action as a general requirement rather than speaking directly to you.
Compare:
Manuals often prefer impersonal wording.
With brancher, French often uses à to show what something is being connected to.
So:
The pattern is:
Examples:
In English, we often say into, but French commonly uses à after brancher.
French often uses an infinitive like this when the subject is understood from the context.
So:
means:
The person doing the using is the same implied person reading or following the instructions. French does not need to repeat vous here.
French uses articles more often than English does.
In English, instruction-style sentences sometimes omit articles or use possessives:
French usually sounds more natural with articles:
So even where English might sound more compact, French often keeps the:
The sentence breaks down like this:
So the overall structure is:
[The manual says] + [that it is necessary] + [to do X] + [before doing Y].
This is a very common French pattern in formal instructions.