There is often a misconception when people are introduced to Human Design that only the Manifestor type can manifest. But that is simply not true. We can all manifest if we do it by our design. A basic rule of thumb starts with the strategy of the type. Manifestors manifest by informing who they impact, Manifesting Generators manifest by acting, responding etc., Generators manifest by responding, Projectors manifest when they are invited and Reflecrtors manifest when they reflect.
As you start to understand more about the high level strategy you can begin to fine tune it even more. For example, if you are a 1-3 profile you are designed to manifest a particular thing, when you have a foundational understanding and you have experienced enough to make it work. If you are a 5-2 profile you have the opportunity to manifest when you draw people in. If you have the leadership gate, gate 7 then you are designed to manifest while leading. So there are many factors built into your design that effect how you manifest.
In addition to aspects like profile and gates you should take a closer look at the Throat center. After all in Human Design all expression comes to the surface in the throat. The connections you have there can influence how much initiation will work for you. If you are a true Manifestor type then you can initiate a lot. If you are a manifesting generator then you can initiate some but it typically works better to initiate by response. If you have a defined throat and are a projector then there maybe certain things you can initiate but usually it will work better to initiate after invitation. Lastly if you have an open throat then your manifestation will be best by invitation, response or reflection.