Any idea's how I start this code process as pro-bono.
You can try searching the website of "the district court in a county in which the property is located" to see if they have any guidance for would-be pro se filers on filing this type of petition in that court. Or you could see if you can find a lawyer willing to handle this fairly simple job for a reasonable fixed fee.
Before you file your petition, though, make sure
(1) you paid your brother's share of the property taxes for at least 3 years and your brother has owned his share but failed to chip in on the property taxes for at least 5 years, and
(2) you've sent your brother an itemized request for payment of his fair share and can prove to the court that you did so.
BTW, if it were me, in my mailing I'd also request payment of his fair share of the other expenses, because he should pay them, of course, but also because an all-encompassing request is less likely to alert him to what you are planning next.