arrage for strings

I have composed many songs all of indian nature..

Iam truing for western ones these days...I am not sure of the concept of strings. infact iam new to 1st violin 2nd viola cello and recorder... does an electric bass conflict with the frequncy of cello?

Bass and cello are completely different. While the bass is an octave lower, it can only reach to the E 3 octaves below middle C (unless it has a C extension which makes it the C 4 octaves below middle C). Unless the part is for some virtuostic electric bassist, the bass shouldn't enter the same frequency as a cello (which ranges from the C 2 octaves below middle C and can go well over 2 octaves above middle C (again, usually only perfessionals or highly talented cellists can get that high). Good luck on your western music; from what I know, it is usually quite fast paced and often is written in attempt to imitate a horse galloping. I actually think that a horn is rather western or a muted trumpet (again, a typical but not necessarily required aspect).

May I suggest studying some standard string scores (quartets and string orchestra) while listening to decent performances of the works. Strings provide a whole mass of timbres and articulations and you need to find out how the different sounds are notated; and how the harmony is laid out to give particular effects. Basically, the standard layout, violin 1, violin 2, viola and cello are to do with four part harmony, reflecting, centuries ago, what was happening with voices. The compass of the string orchestra however, far exceeds that of voices in four parts so you can take advantage of that in laying out out the parts.

Until recently, double basses generally doubled cellos at the octave below when used at all. If the basses are doubling cellos that drop below the bottom E, the bases play the relevant notes in unison with the cellos...usually.

There's no reason why you shouldn't integrate electric/electronic instruments with strings if your composition suggests it.