JavaCard OS

I have been done much research on how to install applet to java cards, and I've figured out the whole Load and Install APDUs. But I don't know which commands need to be sent to the card before the start of the loading. I am a little confused about this. Here are my questions.
a. Do I need to select the OPEN -application before sending Load+Install commands?
b. And also, do I need to open some kinds of secure channel?

Utyr2017 wrote:a. Do I need to select the OPEN -application before sending Load+Install commands?

Yes. You need to select the Issuer Security Domain.

Utyr2017 wrote:b. And also, do I need to open some kinds of secure channel?

Yes. You need to open a secure channel. This process includes the INITIALIZE UPDATE and EXTERNAL AUTHENTICATE commands.

Do you particularly want to code this or it sufficient to just use a tool? There are plenty (pyApduTool, GPShell, GlobalPlatformPro, etc etc) and if you are looking to implement in code there are a few good libraries out there, depending on which language you want to use.