hi there i am pretty new here but have been 3d printing for about 8months .... i have run into this problem with some files in the past but managed to avoid the problem by just finding alternative files from another source but now find the need to figure it out as there are no other good sources for the files i want.

so now the problem is that i have these .STL files that i want to print but when i open them into my slicer(cura) they are just tiny and i dont know how to fix them for printing, i do know how to resize but i dont know the size they should be.... is there a way to fix this or am i just out of luck unless i keep guessing and trying till i get size right? because thats not gonna happen as these are big, long prints like 10hrs+ ...

please help me out and thanks in advance...