Turn a problem into a solution hypothesis, prototype it lightly and record what people do.
In Founder mode, open PROVE in the founder sidebar and choose Solution & Prototype. A solution here is a hypothesis to test, not a product to build — it can change, and a prototype can be thrown away.
Press Define a solution and pick what you are trying to solve: one of your opportunities, one of your problems, or Create without linking. Who has the problem and what they use today are filled in from what you linked, so you do not write them twice. One problem can have several solutions — Another solution for this adds the next one.
On the Solution tab, fill in We believe [solution] can help [customer] solve [problem] by [how], resulting in [outcome], and the value proposition: for whom, which problem, what you provide, the outcome, and better than what. The page drafts each sentence from your own words; use the draft and edit it. Add how it would work in four steps and what you are trying to learn.
On the Prototype tab, create something lightweight — a sketch, wireframe, clickable mockup, landing page, spreadsheet, manual service or demo. Say what it tests and who it is for, and add a link or attach an image or PDF (only you can see it). A prototype is something you use to learn; it is not an MVP.
On Test with people, press Record a test for each person who tries it: what they tried to do, what actually happened, whether they could do it, what they said and what they did. Add evidence entries too — each is marked observed, said or a signal, because what people do is stronger evidence than what they say.
On What we learned, the page lays what people did, what they said, your interpretation and what is still unknown side by side. List what worked, what did not and what you still do not know, track the assumptions the solution rests on (untested, testing, supported, contradicted, discarded), and mark the steps of the evidence ladder you have actually seen, from interesting to I will pay and I will recommend it.
When testing changes your mind, create the next prototype version and say what the last one taught you, or start a new version of the solution. Earlier versions, their tests and what they taught stay readable — nothing is overwritten.
The page suggests one next thing to test — for example, put it in front of three people, or find out whether they would pay. Compare several solutions side by side by their evidence. Only you mark the evidence Promising, after a review; from there, Business Model and Product & MVP are the next places to go.
Open Design and test a solution before building it in the app (sign-in required).