android studio and sdk is not working

hello everyone,i am trying to develope a game for android plateform , so i download android studio and install it but there is no android sdk in it . someone suggested me to download android sdk separately and install plateform tools and other stuff. so i tried this solution but there is no option to download plateform tools and other things.sorry for my poor english.but i really need help…thanks

@jotSMahal still same problem. i downloaded android sdk from fileHippo and installed it but the problem is same. there is no option in sdk manager to download anything.

When you install Android Studio and Unity on the same PC, use a different Android SDK (and NDK) location for these.

first of all thanks guys for your effort to solve my problem . i think i found my mistake .so i think i should write the exact method .
step 1; install java jdk (version 9 have some issue so i downloaded version 8) .

step 2; set java variable path and i think this the main mistake i have made earlier.

step 3 . download and install android sdk . i have downloaded older version of sdk.

step 4 open sdk manager and download plateform tools ,plateforms ,build tools and other necessary stuffs.

step. 5; change the tools with tools .r25.2.3 (in my case this version is working fine );.

thanks again guys…