Hello Sumeet.
Regarding point b)
With the native SAP HANA Content Transport system you are able to transport delivery units/products or changes. It is not necessary to download them from the source system and import them in the target system manually. By defining a target system this is done automatically. Please have a look to slides 47 - 49 in the linked document.
Regarding point c)
CTS+ is the enhanced CTS system which allows you to transport non-ABAP content. So if you have already a CTS+ system in your landscape (or wanna introduce it to it), it is possible to transport delivery units or changes via CTS+. Technically the HANA artifacts are exported into a container (tgz file) which is attached to a CTS+ transport. On the target systems the container is extracted and the deployment process for the HANA artifacts is started.
For more information regarding CTS+ please have a look to Resources on CTS+.
Regarding your other questions
Set up of transport system landscape is part of Basis guys.
Creation of transport, assignment of objects depends on your project set up. Some projects allows developers to do that, others have so called "Development Coordinators" or an "Implementation Management" (and many more other role definitions) which do that things.
Best Regards,
Florian