Positioning is deciding what you are for, and — harder — what you are not for.
Most companies arrive at it backwards. They commission a logo, then a website, then a campaign, and somewhere in the third round of revisions discover that nobody in the room agrees on what the business actually is. Every one of those rounds is being billed at design rates to settle a question that costs nothing to answer in a conversation.
A position is not a slogan and it is not a mission statement. It is a decision with consequences: which customers you turn down, which work you stop taking, which competitor you are willing to lose to on price. If your positioning has not cost you anything, it has not positioned you.
The output is usually short. A sentence, sometimes two, that the founder can say without wincing and the sales team can say without translating. Everything downstream gets faster once it exists, because there is finally something to be consistent with.
Do it first. It is the least glamorous week of the project and the only one that makes the rest of them shorter.