As the PSU bay is located in the very top, one has to install the PSU first to avoid any issues later on. The compact nature of the chassis will also require you to insert all internal 3.5" drives before installing the motherboard and CPU cooler.
Installing the motherboard is a tight fit and the large top-blow cooler does, as you can see, block the two internal hard drive bays to the right of it. This is due to the unfortunate combination of central socket placement on the AsRock motherboard and the large 140 mm-based CPU cooler. You should use a 120 mm tower cooler or AIO liquid cooler instead to ensure that all the drive bays remain usable.
The floor of the chassis can easily hold either hard drive pictured above. Regardless of which one you pick, you will need to use the included screws to secure the drive in place. You can, while I have installed them with the connectors facing towards the rear of the chassis, also turn the installed drive around to connect the cables through the front.
Installing the optical drive bay within the case requires you to pull the front off before removing the cover of your choice first. Once free, simply slide the drive into place and apply the locks. This does hold the drive well enough to keep it from unfastening during transport but not as well as screws, which may lead to noise due to vibration. I suggest using a screw or two on top of these locks.
With everything installed and some time invested into tidying things up as best as possible, the Rosewill Line-M manages to make a good and fairly clean impression. The opening in the motherboard tray unfortunately doesn't cover all the possible socket locations, as the use of the AsRock Z77 board shows.
The blue power light and the blue LEDs in the fan make it, once turned on, quite apparent that the unit is up and running. While the LEDs are a nice touch for younger users, such lighting may be frowned upon in an office environment.
The optical drive fits well within the Line-M. One can clearly see the white fan of the CPU cooler within the case through the openings on the side. There is very little space between CPU cooler and side panel, which means that you really have to watch things when installing cooling fans there. Everything in the rear is accessible and where you would expect it to be in a chassis of this type.