You need to install aria2.

sudo apt install aria2

Now download like this:

aria2c -c -x 16 -s 16 [url]

Explanation of options
-c, –continue[=true|false]

Continue downloading a partially downloaded file. Use this option to resume a download started by a web browser or another program which downloads files sequentially from the beginning. Currently this option is only applicable to HTTP(S)/FTP downloads.

-x, –max-connection-per-server=NUM The maximum number of connections to one server for each download. Possible Values: 1-16 Default: 1

-s, –split=N Download a file using N connections. If more than N URIs are given, first N URIs are used and remaining URLs are used for backup. If less than N URIs are given, those URLs are used more than once so that N connections total are made simultaneously. The number of connections to the same host is restricted by the –max-connection-per-server option. See also the –min-split-size option. Possible Values: 1-* Default: 5

You can create an alias or bash script if you dont want to remember the options.

echo Download Manager by Joel - uses aria2
echo Downloading $fl
aria2c -c -x 16 -s 16 $fl