How do I set up SAP Basis?

I am a new Basis administrator, and our systems are:
* SAP R/3 4.6C ( support patch: KA47, KB47, KH47 and KE84)
* Kernel 4.6D (Support Patch Level: 988)
* Solaris operating system is 64-bit, and Oracle database is 32-bit.
My questions:

1. How can I find out if our SAP kernel is 32-bit or 64-bit? I found only saposcol file is 64-bit, most of the files are 32-bit.
2. Do I have to download both DB-independent and DB-dependent files in order to upgrade our SAP kernel?
3. Do I have to download all files in DB-independent and DB-dependent into our system? Or just some files:
DB-independent: dw 1969, R3trans 1953, SAPEXE 1747, SAPEXE 1805, SAPEXE 1883, SAPEXE1913 and tp 1967. DB-dependent: SAPEXEDB, SAPEXEDB 1805, SAPEXEDB 1883, and SAPEXEDB 1913).

Run "disp+work -version". If you do NOT see anything saying, "compiled with 64-bit libraries," then your system is running the 32-bit R/3 kernel version.
Also, I encourage you to take a look at SAP Note 192822 titled, "FAQ: 32-bit/64-bit R/3-Oracle."
I am going to quote a section of this note for you:

"For all current releases, the patches are stored in the SAP service marketplace http://service.sap.com/swcenter_3pmain . After choosing Oracle, you have the option to go down the oracle 32-bit or oracle 64-bit path. Please note that in order to decide which of the two to choose the only thing tht matters is what bit version your Oracle software is. No matter whether your OS is 64-bit; as long as your Oracle is still 32-bit you would go down the Oracle 32-bit path."

2. Yes. You need both. Otherwise, the system will not work properly or won't even start at all.

3. You need to download the latest versions or at least one version before the last one.

In the example above, you should download these files: DW_1969, R3trans_1953, SAPEXE_1913, TP_1967 SAPEXEDB_1913 Then, you need to decompress each archive (.SAR) file using SAPCAR -XVF.