I'm shifting to Nairobi on august.

Hello,
As your father will be working, you will probably be issued with a 'Dependents Pass'.  This will allow you to remain in Kenya, but does not permit you to work. 

If you wish to work, then you need to secure a job offer, after which you apply for a work permit.  Your employer is generally fully involved in this process as they must evidence to the government that the position cannot be filled from the local workforce (Kenya has a lot of unemployed graduates, with Degrees and Masters Degrees).  The work permit process can take 3 - 4 months and if agreed, there is a fee of Kes 200 000 plus other fees, for a period of two years.  There is more information on permits and passes at the link below:

http://www.immigration.go.ke/index.php? … Itemid=127

Good luck!