@umarkhan74
Welcome to PW bro 
You can purchase your equipment from Higher: Higher Adventure Rescue Relief Equipment Pakistan
You need to initially buy following for multiple days trekking trips:
1- Sleeping bag
2- Sleeping foam mat
3- Hiking stick
4- Dome Tent (2-3 person) - water proof must
5- Rain coat
6- Hiking / trekking shoes - keep extra pair of joggers. slippers optional
7- Flashlight, head lamp etc.
8- Bag-pack - big one for all packing - 70 ltrs
9- Shoulder bag - for walking, trekking - with rain cover
10- Knife / swiss knife
11- Stove
12- Packed food
13- Ropes
14- Gaiters for snow
15- Plastic cover for your luggage and other stuff which cannot be put in camps
16- Water bottle
This is not an exhaustive list but u can make a start by getting these things. Most of these are one time expenditures and will be used in future trips.
