This download looks like a lua file. You need to place it in your lua folder inside the Garry's Mod folder.
You should end up with a directory structure similar to below:
-
steamapps
-
common
-
garrysmod
-
garrysmod
-
lua
-
autorun
- readme.txt
- lua/
- entities/
- sent_Sakarias_Car_yamahayfz450/
- cl_init.lua
- init.lua
- shared.lua
- materials/
- models/
- tiggogm/
- vehicles/
- yamahayfz450/
- 32_1.vmt
- 32_1.vtf
- 512CFWEAVE2.vmt
- 512CFWEAVE2.vtf
- 5et254470000-500.vmt
- 5et254470000-500.vtf
- chrome3hw7.vmt
- chrome3hw7.vtf
- Deselecciondsfsar.vmt
- Deselecciondsfsar.vtf
- gyt-5tg93-70-tt-500.vmt
- gyt-5tg93-70-tt-500.vtf
- gyt-5xc35-10-al-500.vmt
- gyt-5xc35-10-al-500.vtf
- Houser 2.vmt
- Houser 2.vtf
- LICENSE_1.vmt
- LICENSE_1.vtf
- Metal colao.vmt
- Metal colao.vtf
- metal red.vmt
- metal red.vtf
- metal.vmt
- metal.vtf
- metalsornamentalmetalspew8.vmt
- metalsornamentalmetalspew8.vtf
- motor3.vmt
- motor3.vtf
- motor4.vmt
- motor4.vtf
- nylon red.vmt
- nylon red.vtf
- Nylon Yellow.vmt
- Nylon Yellow.vtf
- nylon.vmt
- nylon.vtf
- remapquadbody128.vmt
- remapquadbody128.vtf
- remschijven abm.vmt
- remschijven abm.vtf
- skin.vmt
- skin.vtf
- skin1.vmt
- skin1.vtf
- skin2.vmt
- skin2.vtf
- skin3.vmt
- skin3.vtf
- tex.vmt
- tex.vtf
- tex2.vmt
- tex2.vtf
- tex3.vmt
- tex3.vtf
- tex4.vmt
- tex4.vtf
- tex5.vmt
- tex5.vtf
- tex6.vmt
- tex6.vtf
- VGUI/
- entities/
- sent_Sakarias_Car_yamahayfz450.vmt
- sent_Sakarias_Car_yamahayfz450.vtf
- models/
- tiggogm/
- vehicles/
- yamahayfz450.dx80.vtx
- yamahayfz450.dx90.vtx
- yamahayfz450.mdl
- yamahayfz450.phy
- yamahayfz450.sw.vtx
- yamahayfz450.vvd
- yamahayfz450wheel.dx80.vtx
- yamahayfz450wheel.dx90.vtx
- yamahayfz450wheel.mdl
- yamahayfz450wheel.phy
- yamahayfz450wheel.sw.vtx
- yamahayfz450wheel.vvd
