How do you get thourgh lavabrigde gym

To get to Lavaridge, you need to go up the mountain in the cable car, you need to do something before you do this so you can get up the mountain. Battle through the Team Magma members to acquire a meteor, this comes in later for Professor Cosmo of Fallabor Town. Make your way back down the stairs, don't go back to the cable car, keep walking south, enter Jagged Pass and make your way south, keep going until you get out and see a hiker pacing on your right. I think you can battle him, if you don't want to walk to your left and then you enter Lavaridge.
Hope I helped!