There are many, many ways to walk in-game with Simba, below I'll list a few and a bit of explanation for each.
SPS (SRL Positioning System)
The most commonly used method, for locating and positioning, would be SPS. This method compares your mini-map to 500x500 chunks of the full RS game map to determine your current location. It's easy to use and very accurate in EoC & RS3, but accuracy is low if you choose to use this in OSRS.
ObjDTMs
Another popular method is a system called ObjDTMs created by euphemism. What this does is uses common objects on your minimap to find a specific point. If you're familiar with DTMs then you'll understand this works the same way except instead of static colors for the sub-points, minimap objects are used. There's a nifty little tool for creating ObjDTMs for area locating and path walking. A down side of using this method is it's not yet converted to be compatible with OSRS but I've heard it's on the to-do list.
(D)DTMs
These are quite simple to make as Simba comes standard with a DDTM tool built-in. This method can be quite accurate if the DDTMs are make right. This is
probably the most commonly used method for OSRS because of the inaccuracy of SPS and ObjDTMs in this version of RS. But don't underestimate (D)DTMs as I've seen both a Pest Control and Soul Wars script made with the positioning and walking done 100% with DDTMs. As I said before, if you make & use these right they'll never fail you.
Radial & Linear walking
I've never used this method before and, because the SRL forums are down at the moment, I cannot add much information to this, sorry...
