Hallo friends.

If I dowload some tracks extension file .sv6 or .sv4 and I save it inside folder called "tracks" in my RCT game after I dont see the tracks when I play. I can build only tracks of default game.

I wrong something?

Thank you so much

You are confusing formats.

SV4 / SV6 are saved games and go in the Saved Games folder.

TD4 / TD6 are tracks and go in the Tracks folder.

SC4 / SC6 are scenarios and go in the Scenarios folder.

The ones with "4" are for RCT1, the ones with "6" are for RCT2.

Oh sorry, I was very wrong.
Thank you so much for your useful information.

PS: Do you know too why in RCT2 In cant change the price of rides? Always are in "GRATIS" and I cant change

RCT2 is made in such a way that a scenario can have either purchasable ride tickets or park entrance tickets, never both. That is something pre-defined for every scenario and you can't change that in RCT2 vanilla, BUT you should be able to use OpenRCT2's editors to basically re-save the scenarios with the RCT1 setting.