My question is what power do the people have in this situation? Can the people lawfully bypass the politics and have the president removed?
When i watch A DJT speech or read certain drops the message of we the people will trigger the storm resonates with me. Do we need to show the military that we want change for them to step in and make the arrests?

Q 1
Can they arrest a President or does he have to be impeached?

If you are talking about 1) arresting a Pres then 2) they step down before 3) impeachment* in Congress, and 4) Criminal trail in the Senate - no; it does not work like that.

First there is impeachment in Congress then you have a Formal arrest but only after a guilty verdict by the (criminal) trial in the Senate

*think of impeachment as formally putting together a case to a court, and the Senate is the body that actually (criminally) tries the case

Q 2
Not sure we have ever crossed the bridge before of a President illegally seated by a foreign power.

-I'm sure there have been 'whispers' or rumors of that happening before, but to my knowledge, we haven't actually done anything about it

Q3

Can he be arrested via military for treason and held until court?

-I'll say maybe, especially since the President is the Commander in Chief of the military

No. Wishful thinking.

i agreed if he was lawfully elected then no he can not be arrested he has to be impeached or they would have arrested DJT. perfect example but if a military court has evidence of fraudulent election and foreign interface then they have the authority to arrested and detain domestic terrorists. treason punisable by death.