How do you spawn institutions?

[Aksolotli]

Let's say i wanna play Kongo, Russia or Mughals. How do i spawn institutions?
I could do few practice France, Spain, Netherlands runs to practice spawning them.

[Khatulistiwa]

First wait until the constitution is available, then just develop a province until the gauge is filled up, then it will start spreading to neighboring provinces

[Totally Innocent Chatbot]

First, obviously, wait for the Institution in question to actually appear in the world. Then, find a province where you can stack as many development cost modifiers as possible (your capital is usually a good candidate for the first one, since it receives a hefty dev cost reduction based on how much total development your country already owns). Every time you develop a province, a bit of progress towards the oldest unembraced Institution appears in that province (with the exception of Feudalism for New World/Australian natives). So, you need to keep developing that one province until progress there reaches 100%, at which point it will be fully present there and begin to spread to adjacent provinces. Wait for it to spread if necessary (it must be fully present in at least 10% of your country's autonomy-modified development before it can be embraced), then spend the money to embrace it (if you're at risk of falling behind on technology, it is worth taking out a few loans to have the money).

Exactly how long you can afford to wait for the Institution to spread from that one province will always depend on your current situation, so there is no one "correct" answer here. Also be aware that the current development of a province affects how much institution progress each dev click gives - the lowest-dev province or current cheapest per point won't necessarily be the best province overall, as you'll need more total dev clicks that might add up to more overall mana spent. The total amount of mana you need to spend to force Institution spawn in one province, before cost modifiers, is around 1900-2400 depending on starting development (the best starting value is actually 16 dev), but you can get that number down significantly from stacking dev cost modifiers.

If on the other hand you mean being the one in whom the Institution actually originates, that's another issue entirely. Each Institution has its own specific requirements for where it can spawn, which are flatly impossible to meet for some nations (Renaissance can only spawn in the Italy region, Printing Press only in the North or South Germany regions or any Protestant or Reformed province). Check the wiki or the Institutions menu in-game for more detailed information for each Institution's spawn requirements.