Ukraine's preparation for the use of Javelin anti-tank missile systems that the US plans to send to Ukraine should not cause difficulties. Issues could potentially arise with somewhat more sophisticated arms systems that require special personnel training, technical preparations. Javelin is a simplified operational use system.
The military will be trained by foreign experts. But I would advise our American partners to train Ukrainian instructors, who could later prepare calculations for anti-missile systems in the field.
As far as I know, the US is talking about the delivery of 35 Javelin reusable missile launchers with 210 missiles.
Obviously, delivery of American weapons to Ukraine is of great importance, as there used to be an unspoken restriction on the supply of weapons to Kyiv due to Russia being our enemy. And although Canada also approved export licensing, and Lithuania has long been supplying Soviet-design weapons and ammunition to our country, Washington's decision is sending a message to others that Ukraine can be a partner in this field.