Install packages dont work

[DeepakTivari]

I am trying to install a package:

I added this to my conf.el file:
; use ledger mode for files ending with ".ledger"
(package-install 'ledger-mode)
(require 'ledger-mode)

But i am getting:
Debugger entered--Lisp error: (error "package.el is not yet initialized!")
signal(error ("package.el is not yet initialized!"))
error("package.el is not yet initialized!")
package-installed-p(ledger-mode nil)
package-compute-transaction(nil ((ledger-mode)))
package-install(ledger-mode)
eval-buffer(#<buffer load-789299> nil "/home/delta/.emacs.d/personal/preload/conf.el" nil t) ;

I don't see any documentation or guideline to install own packages, please point me to any resource

[FredeEB]

Under Tips here:
https://prelude.emacsredux.com/en/latest/configuration/#personalizing

it says

If you'd like to add some auto installation of packages in your personal config use the following code:

(prelude-require-packages '(some-package some-other-package))

If you require just a single package you can also use:

(prelude-require-package 'some-package)

So you'd do:
(prelude-require-package 'ledger-mode)

[DeepakTivari]

This is exactly what i put in my custom conf.el
; Install ledger-mode package
(prelude-require-package 'ledger-mode)

However this is the error i got:

Symbol's function definition is void: prelude-require-package

To ensure normal operation, you should investigate and remove the
cause of the error in your initialization file. Start Emacs with
the ‘--debug-init’ option to view a complete error backtrace.

[ryukinix]

@DeepakTivari

You need to add on top of you conf.el:

(require 'prelude-package)

Which means:

(require 'prelude-package)
(prelude-require-package 'ledger-mode)

See a full functional example here.