A. The first step is to erect you water source (the 100 litre drum/tank)
With foresight, the final drip irrigation system layout should resemble something along this:-
The first step after sizing the field, is to build/construct a foundation/stand either from concrete, metal or from wood (wood/timber) is the cheapest and yet as equally durable if treated, and effective, as the previous two).
The key consideration is to ensure that the height of the stand/foundation/base from the ground is between 1-1.5m.
Less than 1m, and the pressure of water flow is much reduced. Water easily fails to reach the farthest crops in the row/lateral.
Again above 1.5m, and the irrigation pipes could bust due to too much pressure of water.
Overall, make sure to check the pressure and water ratings of the irrigation pipes from the manufacturers manual when deciding to which height to raise your drum/tank. But overall, 1-1.5 is optimum.
You can then raise up and steady the tank/drum on the stand, ready to fill with water.
B. Next is to lay the irrigation pipes/drip tape.
The rule of thumb is that this being a simple drip irrigation system which will use gravity for pressure (water source is a water tank set at least 1 meter up), make sure that the main lateral is on the top of the slope.
a) Here, i am unrolling the drip tape ready for laying on the garden.
b) Here now the pipes are being laid with the help of farmers.
It is important to ensure that laterals are well laid, running parallel to each other down slope.
c) Drip lines now well laid
Now your simple drip irrigation system is well laid, and ready for plants/seedlings to be transferred to along its dripping points/emitters.
Congratulations!!