Buying Inverter Generator - Cable to Transfer switch

Hey Guys, I am comfortable working safely with electric and have done so on many smaller 110 projects, but not sure if I can handle this. I bought this house a year ago which had a 240 line run to a junction box in the garage for a large compressor by the previous owner. In the process of selling they had an electrician install a new panel. they disconnected the 240 line and took the wire. I would like to add a garage heater and this seems the better option because the EMT is run and I dont have to vent out the garage wall. Attached are picture showing the junction box in the garage under a work bench. where they disconnected the EMT just to the right of the panel, the panel itself which only has two openings, and the label with the part number for the panel. So how would I re-establish this? 1. i would have move connections in the panel to get two opening on one side for the 240 2 pole breaker. or is the panel rated for tandem breakers? 2. establish a 240 outlet or direct wire it to the garage heater? I am sure its best to hire an electrician, and have it inspected. just wondering my options as electricians in Chicago are more expensive than most places in the U.S.

Based on some web searches, I have come to the understanding that "3-way switch" actually means two switches controlling the same light (or outlet). So then, what is a 3-switch configuration called? Is is called 4-way or 5-way, or something else? For example, I have a foyer chandelier where the foyer is located at split level; in other words, the front entrance to the home is half way between the lower floor and the upper floor. The chandelier light can be controlled from switch next the front door (which, again, is at split level), from a switch near the bottom of the steps down to the lower floor, and from a switch from the upper floor. Since "3-way switch" means a two-switch system, what is a 3 switch configuration called? The second part of my question pertains to use of dimmers in multi-switch scenarios. Based on references I've found, I gather that using a dimmer with a "3-way switch" involves installing 1 dimmer, not two. In other words, a decision about which switch would be replaced by the dimmer must be made before a dimmer can be added to the system. This means the light fixture can be dimmed from one switch location, not both. Is that right? doityourself.com has an article on this at [url]https://www.doityourself.com/stry/installing-three-way-dimmer-switch[/url]. In the first paragraph, it says "The primary thing that confuses most do-it-yourselfers is the fact that only one of the three-way switches needs to be replaced with the dimmer switch." So, I gather that dimmers cannot be used on both switches of a "3-way switch". Is that right? If the answer to the is yes, is the decision about switch standard switch to replace with a dimmer simply a matter of preference? And, if the light is off, with dimmer set to a dimmed setting, does that dimmer setting control the brightness even when the light is turned on via the standard switch, i.e. the other switch?