Finding current through thevenin theorem
Below, I've redrawn the schematic:







simulate this circuit &ndash; Schematic created using CircuitLab

It's exactly the same as the one you have drawn out. I just picked one of the shared nodes to be ground and worked from there.

Does this help you analyze the circuit? Using nodal analysis, this isn't too hard.

But you can also use mesh analysis -- perhaps easier for you in this case:







simulate this circuit

Here, you'd solve for three currents using three easily developed equations and then find the difference between \$I_1\$ and \$I_3\$ to work out the current in the \$10\:\Omega\$ resistor.



Given your comments now about how you are supposed to solve this, look at the following:







simulate this circuit

Here, I've removed the \$10\:\Omega\$ resistor from the circuit and, in its place, provided nodes \$A\$ and \$B\$ where it used to be. (I've decided to ground the left side.) You should be able to work out the Thevenin equivalent at node \$A\$, now. (\$B\$ is ground.) Once you have \$V_\text{TH}\$ and \$R_\text{TH}\$, you can then re-insert the \$10\:\Omega\$ resistor and work out the current in it.