Here are a few suggestions to start with the simulation of the meander line antenna:
First simulate any other antenna (maybe patch antenna or planar dipole antenna) using Antenna Toolkit to learn about the various nodes (such as Excitations, Boundaries, Analysis Setup, Frequency sweep, Far Field Radiation Setup, etc.) that need to be assigned / set.
Create the geometry of the meander line antenna in HFSS, assign various nodes, and simulate the design. You may assign variables for the various dimensions of the antenna, just to parametrize them, in case you need.