Question concerning n-MOSFET switching
Basic operation:

Think of the FET as an on/off switch or tap.   

Current flow is as water current flow.
 Power supply or battery is like a pump or head of water.
 Load is like a hydraulic motor or a weir that drops water head or a hole in a pipe that drops pressure as the water escapes.   

Current flows FROM pump through load through switch back to pump inlet.  

OR

Current flows FROM pump through switch then through load then back to pump inlet.  

Either way current MUST flow through switch and load regardless of what order thy are in. 



MOSFET CHOICE:

A properly specified MOSFET will easily meet your requirement.
 The one you have indicated is a good one for high voltage applications but totally unsuited to this task due to its very high on resistance = Rdson .
 This high resistance is a feature of the high voltage capability of the MOSFET and will not be a major issue in its intended role.
 A MOSFET to meet your need can have a rated voltage Vds of say 10V or more but 20V or30V parts are safer and as cheap, and a rated current of say 5A, but 10A to 30A or even 50A parts are also often as cheap and have some advantages.  

If a part with Rdson = 0.1 ohm is chosen then on dissipation at 2A = I^2R = 2^2 x 0.1 = 0.4 Watt. A TO220 package will run at this power level with no heatsinking and a DPak package surface device  needs only modest copper heatsinking. If Rdson is say 0.02 ohm (easily achieved with modern devices) dissipation at 2A = 2^2 x 0.020 = 0.08W ~= 00.1 Wa and no heatsinking is needed with the above devices

**What is your system Vdd - ie what drive voltage is available?
 2V / 3V3 / 5V /  more ...
Very important for FET selection.

Suitable MOSFET:

I did a Digikey search for 30v+, 10A+ NChannel MOSFTS with 2V max gate turn on voltage

Cheapest stocked item is a SMD package but hobbyist almost friendly
 NXP (Philips) PSMN9R5-30YL - datasheet
 63c/1 Digikey in stock
30V, 44A !, 9.8 milliohm !!!
 Rson is not nice at 2.5V Vgs but is under 15 milliohm at 3V.
 ie driving in a 3.3V or more system is good.

ST brand DPak 
STB85NF3L - datasheet 

30v, 85A !!!,
 Good at 3V drive
 Superb at 5V drive
About Under 80c/1.

[TO220 STP55NF06 60V 55A $1.56/1 but TO220 may suit.](
STP55NF06)
 Good at 2.5V gate drive
 Superb at 34V gate drive
 Works ~~ at 2V gate drive.



You do not say what the load is.
If it is inductive it MUST have a reverse diode placed across it. 
 1 x 1N400x will probably suffice.

If it is not inductive a reverse diode will not hurt, costs a few cents and will save you if the load is in fact more inductive than expected.
 Murphy lurks everywhere.